Re: [Emacs-diffs] feature/byte-switch 086c4ea: * src/bytecode.c: (exec_byte_code) Use hash_lookup for Bswitch

[Vibhav Pant]

On another thought, `byte-switch` is used while compiling certain
`cond` forms. It
replaces the traditional goto-if-nil bytecode by using a hash table mapping
values to addresses/tags to be jumped to. Since `byte-switch` is essentially a
"dynamic" goto (in the sense that the address/tag cannot be known at
compile time),
wouldn't doing a runtime type check in the bytecode VM for what is  a
hash table lookup + goto have a significant performance penalty?

On Wed, Jan 18, 2017 at 11:18 PM, Stefan Monnier
<address@hidden> wrote:
>>     * src/bytecode.c: (exec_byte_code) Use hash_lookup for Bswitch
>>     Fgethash type checks the provided table object, which is unnecessary
>>     for compiled bytecode.
>
> While it's true that we can cause a core dump of Emacs if we feed it an
> invalid .elc file, that's a "feature" I'd rather shrink rather
> than generalize.
>
>
>         Stefan



-- 
Vibhav Pant
address@hidden